Traditionally, elevator cab design requires walls forming the interior of the elevator in the form of shell panels mounted between a platform and ceiling. Further the shell panels are traditionally stiffened by vertical stiffeners on the exterior of the shell that extend toward the elevator shaft. Decorative panels are mounted on the inside of the shell panels so as to extend into the interior of the elevator cab. Thus the wall thickness will be the sum of the shell wall and the depth of the exterior vertical stiffeners plus the thickness of a decorative panel mounted on the shell. The standard removable decorative panels mounted on the inside of the cab extend into the interior of the cab from the shell as much as one inch or more for each wall so the cab size is reduced by both length and width.
In order to make room for passenger needs an increase in width and depth of the elevator cab can make a significant improvement in the design of new elevators or redesigned old elevators located in limited elevator shaft space.